By previous elements found in other stars, accurate guesses and lots of studying
Answer:
the correct answer is D.) 2,4
Added potential energy = (mass) x (gravity) x (height)
or
Added potential energy = (weight) x (added height)
If you need to lift a 15N box 3m straight up, you have to increase its potential energy by (15 N) x (3 m) = 45 Joules .
Where is that added potential energy supposed to come from ? You could use an electric winch, a steam engine, a gasoline-powered motor, thousands of hamsters running on little treadmills that are are connected to the main pulley somehow, or your own arm muscles. But howEVER you do it, you have to provide <em>45 Joules</em> of WORK in order to increase the potential energy of the box by just that much.
Answer:
6.429 m/s^2.
Explanation:
Using equations of motion,
i. vf = vi + at
ii. vf^2 = vi^2 + 2a*S
iii. S = vi*t + 1/2 * (a*t^2)
Where,
vf = final velocity of the motion
vi = initial velocity of the motion
S = distance travelled
t = time taken to complete the motion
a = acceleration due to gravity
Given:
vi = 0m/s
vf = 45 m/s
t = 7 s
a = ?
Using the i. equation of motion,
vf = vi + at
45 = 0 + a*7
a = 45/7
= 6.429 m/s^2
